There are many reasons that oil well operators want to know the amount of oil and the amount of water being extracted from the reservoir by the well. The fluid typically extracted is a mixture of oil, water, and entrained gas. The gas in the fluid can be removed by a gas separator as is well known in the industry. Accurately determining the amounts of oil and water in the fluid mixture is more difficult.
It is known to measure the density of the fluid produced by the well, as well as the pressure and temperature of the fluid, to calculate in real time the relative amounts of water and oil being produced. Then, using methods well known in the art to adjust for temperature and pressure differences, one can determine the amounts of oil and water produced at a standard temperature and pressure. To do so, however, requires that the densities of each component, at a known pressure and temperature, be known values.
One method of determining the densities of the components is to remove a sample from the production flow and to send the sample to have oil and water densities determined in a laboratory setting. Laboratory analysis is usually done at standard temperature and pressure. Such removal presents several problems. The significant differences in pressures and temperature from production conditions can cause the measured densities to deviate so far from the production densities that the calculations compensating for changes in temperature and pressure become less accurate. Also, conditions within the subterranean environment can change over time. For instance, the fluid reservoir may be treated with steam or chemicals or the flow within the reservoir may change from one segment of the reservoir to another resulting in a potential change of density of one or both of the components. Taking a sample and sending it to a laboratory on a frequent enough basis to detect and account for such changes is burdensome enough that it is usually not done.
Using a coriolis meter in the production flow, which measures the density of the fluid passing through it as part of its normal operation, to determine the densities of the individual components would address these problems. However, some past efforts to do this have involved interrupting the operation of the pump for significant portions of time to allow the fluid to separate into components within the production tubing and thereby reduced the total fluid output of the well. The apparatus of the present invention overcomes these limitations.
It would therefore be desirable to have an apparatus that could provide for the sampling of component densities, and which would be constructed to be both reliable and long-lasting, and which would overcome many of the disadvantages and limitations of the background art discussed above. Additionally, it would be desirable if the apparatus required little or no maintenance to be provided by the user throughout its operating lifetime. In order to enhance the market appeal of the apparatus of the present disclosure, it should also be of inexpensive construction to thereby afford the apparatus the broadest possible market.
Embodiments of the present invention provide such a component density sampling apparatus. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.